The person confirmed Detroit's objection on condition of anonymity Monday because the NFL is not commenting on the matter. The 27-year-old Johnson is coming off a productive season as a backup for the Lions. He had six sacks, the third-most on the team.
According to the collective bargaining agreement, a dispute over an offer sheet is to be resolved by an arbitrator, who identifies what terms would have to be matched by the player's current team.
Johnson played for Tampa Bay in 2011 and 2012, and he also played for Minnesota in late 2012. The Lions signed him a year ago.